Place n points in general position on each side of an equilateral triangle, and join every pair of the 3*n+3 boundary points by a chord; sequence gives number of regions in the resulting planar graph.

A367118

Place n points in general position on each side of an equilateral triangle, and join every pair of the 3*n+3 boundary points by a chord; sequence gives number of regions in the resulting planar graph.

Terms

    a(0) =1a(1) =13a(2) =82a(3) =307a(4) =841a(5) =1891a(6) =3718a(7) =6637a(8) =11017a(9) =17281a(10) =25906a(11) =37423a(12) =52417a(13) =71527a(14) =95446a(15) =124921a(16) =160753a(17) =203797a(18) =254962a(19) =315211a(20) =385561a(21) =467083a(22) =560902a(23) =668197a(24) =790201a(25) =928201a(26) =1083538a(27) =1257607a(28) =1451857a(29) =1667791

External references